Evolutionists try to establish an ancestor-descendent relationship between living creatures on the basis of certain perceived structural similarities between them. But some creatures have organs that perform a similar function, but no evolutionary link can be established between them. This similarity is known as analogy, and such organs are called analogical.

Analogical organs are different in structure and development, but the same in functions.22 For example, the wings of birds, bats, and insects are functionally the same, but there is no evolutionary connection among them.

Therefore, evolutionists have been unable to establish any common connection between these similar appendages and have been forced to admit that they are the products of separate developments. For example, the wings of birds and insects must have arisen through different chance events than those through which bats’ wings evolved.

For those who want to establish an evolutionary connection solely on the basis of similarities, this is a major obstacle. They have never been able to explain how a structure as complex as a wing could have come into being by chance, and so must explain this separately for each creature. (See Homology; Homologous organs.) Many other such situations have led evolutionists into an impasse. (See Analogous organ, above.)